Résumé : The Gastrointestinal Tract Cancer Liaison Office (GITCLO) was developed in an attempt to organise the increasing body of clinical research in gastrointestinal tumours in Europe. This paper represents an analysis, by tumour localisation, of the trials collected for the second edition of the GITCLO booklet. The list of co-operative groups, chairmen and study co- ordinators is given with their respective telephone and telefax numbers. A total of 84 trials were collected, conducted by 46 co-operative groups in 14 countries. For each organ and stage of disease, a summary of concepts investigated is given with the references of the study co-ordinator. Obviously, too many questions are raised at the same time. In colorectal cancer, for example, a total of 41 trials exploring 22 concepts are currently open for patients' registration. We hope that the present attempt to clarify the situation of clinical research in the field of gastrointestinal cancers in Europe will speed up therapeutic progress in the best interest of the patients.